transmission/qt/FaviconCache.cc

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/*
* This file Copyright (C) 2012-2015 Mnemosyne LLC
*
* It may be used under the GNU GPL versions 2 or 3
* or any future license endorsed by Mnemosyne LLC.
*
*/
#include <array>
#include <QDir>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QNetworkRequest>
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#include <QStandardPaths>
#include "FaviconCache.h"
/***
****
***/
FaviconCache::FaviconCache() :
nam_(new QNetworkAccessManager(this))
{
connect(nam_, &QNetworkAccessManager::finished, this, &FaviconCache::onRequestFinished);
}
/***
****
***/
namespace
{
QPixmap scale(QPixmap pixmap)
{
return pixmap.scaled(FaviconCache::getIconSize(), Qt::KeepAspectRatio, Qt::SmoothTransformation);
}
QString getCacheDir()
{
auto const base = QStandardPaths::writableLocation(QStandardPaths::CacheLocation);
return QDir(base).absoluteFilePath(QStringLiteral("favicons"));
}
QString getScrapedFile()
{
auto const base = QStandardPaths::writableLocation(QStandardPaths::CacheLocation);
return QDir(base).absoluteFilePath(QStringLiteral("favicons-scraped.txt"));
}
void markUrlAsScraped(QString const& url_str)
{
auto skip_file = QFile(getScrapedFile());
if (skip_file.open(QIODevice::WriteOnly | QIODevice::Text | QIODevice::Append))
{
skip_file.write(url_str.toUtf8());
skip_file.write("\n");
}
}
} // unnamed namespace
void FaviconCache::ensureCacheDirHasBeenScanned()
{
static bool has_been_scanned = false;
if (has_been_scanned)
{
return;
}
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has_been_scanned = true;
// remember which hosts we've asked for a favicon so that we
// don't re-ask them every time we start a new session
auto skip_file = QFile(getScrapedFile());
if (skip_file.open(QIODevice::ReadOnly | QIODevice::Text))
{
while (!skip_file.atEnd())
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{
auto const url = QString::fromUtf8(skip_file.readLine()).trimmed();
auto const key = getKey(QUrl{ url });
keys_.insert({ url, key });
pixmaps_.try_emplace(key);
}
}
// load the cached favicons
auto cache_dir = QDir(getCacheDir());
cache_dir.mkpath(cache_dir.absolutePath());
QStringList const files = cache_dir.entryList(QDir::Files | QDir::Readable);
for (auto const& file : files)
{
QPixmap pixmap(cache_dir.absoluteFilePath(file));
if (!pixmap.isNull())
{
pixmaps_[file] = scale(pixmap);
}
}
}
/***
****
***/
QString FaviconCache::getDisplayName(Key const& key)
{
auto name = key;
name[0] = name.at(0).toTitleCase();
return name;
}
FaviconCache::Key FaviconCache::getKey(QUrl const& url)
{
auto host = url.host();
// remove tld
auto const suffix = url.topLevelDomain();
host.truncate(host.size() - suffix.size());
// remove subdomain
auto const pos = host.indexOf(QLatin1Char('.'));
return pos < 0 ? host : host.remove(0, pos + 1);
}
FaviconCache::Key FaviconCache::getKey(QString const& displayName)
{
return displayName.toLower();
}
QSize FaviconCache::getIconSize()
{
return QSize(16, 16);
}
QPixmap FaviconCache::find(Key const& key)
{
ensureCacheDirHasBeenScanned();
return pixmaps_[key];
}
FaviconCache::Key FaviconCache::add(QString const& url_str)
{
ensureCacheDirHasBeenScanned();
// find or add this url's key
auto k_it = keys_.find(url_str);
if (k_it != keys_.end())
{
return k_it->second;
}
auto const url = QUrl { url_str };
auto const key = getKey(url);
keys_.insert({ url_str, key });
// Try to download a favicon if we don't have one.
// Add a placeholder to prevent repeat downloads.
if (pixmaps_.try_emplace(key).second)
{
markUrlAsScraped(url_str);
auto const scrape = [this](auto const host)
{
auto const schemes = std::array<QString, 2>{
QStringLiteral("http"),
QStringLiteral("https")
};
auto const suffixes = std::array<QString, 5>{
QStringLiteral("gif"),
QStringLiteral("ico"),
QStringLiteral("jpg"),
QStringLiteral("png"),
QStringLiteral("svg")
};
for (auto const& scheme : schemes)
{
for (auto const& suffix : suffixes)
{
auto const path = QStringLiteral("%1://%2/favicon.%3").arg(scheme).arg(host).arg(suffix);
nam_->get(QNetworkRequest(path));
}
}
};
// tracker.domain.com
auto host = url.host();
scrape(host);
auto const delim = QStringLiteral(".");
auto const has_subdomain = host.count(delim) > 1;
if (has_subdomain)
{
auto const original_subdomain = host.left(host.indexOf(delim));
host.remove(0, original_subdomain.size() + 1);
// domain.com
scrape(host);
auto const www = QStringLiteral("www");
if (original_subdomain != www)
{
// www.domain.com
scrape(QStringLiteral("%1.%2").arg(www).arg(host));
}
}
}
return key;
}
void FaviconCache::onRequestFinished(QNetworkReply* reply)
{
auto const key = getKey(reply->url());
QPixmap pixmap;
QByteArray const content = reply->readAll();
if (reply->error() == QNetworkReply::NoError)
{
pixmap.loadFromData(content);
}
if (!pixmap.isNull())
{
// save it in memory...
pixmaps_[key] = scale(pixmap);
// save it on disk...
QDir cache_dir(getCacheDir());
cache_dir.mkpath(cache_dir.absolutePath());
QFile file(cache_dir.absoluteFilePath(key));
file.open(QIODevice::WriteOnly);
file.write(content);
file.close();
// notify listeners
emit pixmapReady(key);
}
reply->deleteLater();
}